With the progress of technology, the panel display has been extensively used in the daily life. Take the liquid crystal display (LCD) panel as an example. The LCD panel mainly comprises an LCD module, a backlight module and a power module. The backlight module uses plural cold cathode fluorescent lamps (CCFL) or external electrode fluorescent lamps (EEFL) as light source, and these lamps are driven by a driving circuit called inverter.
Since the size of the LCD panel becomes larger and larger, the amount and size of the lamps are also increased. However, if the energy provided to each lamp is unequal, the LCD panel may have uneven brightness, and the lifespan of parts of the lamps might be shortened since their aging speed may be accelerated due to the unbalanced energy supply. For ensuring the even brightness of the LCD panel and preventing parts of the lamps from aging acceleratedly, it is needed to detect the current flowing through each lamp and further control it according to the balance state, so as to make the current flowing through each lamp equal. Nevertheless, the conventional detecting method is to couple one end of each lamp to a voltage detecting circuit directly for collecting the working current of each lamp. Then the voltage detecting circuit generates a detecting signal according the collected working current and delivers the detecting signal to a controller, and the controller controls and adjusts the output energy so as to balance the energy provided to each lamp. However, such method cannot accurately detect if the energy provided to each lamp is balanced or not.
Therefore, it is needed to provide a new detecting method to overcome the defects of the aforesaid prior art.